Causes and Risks: Fragility of the long arm of the X chromosome is thought to be a result of increased methylation at the site of the break. The Fragile X accounts for approximately one-third of all X-linked mental retardation in males and one-tenth of that in females. This syndrome occurs in approximately 1 out of 2,000 males and 1 out of 1,000 females.

Prevention: Genetic counseling may be of benefit for prospective parents with a family history of Fragile X syndrome.

Symptoms:

• family history of fragile X syndrome
• mental retardation
• large ears
• oversized testes in the male

Signs and Tests: Measurement of testes in males and a chromosome analysis helps confirm the diagnosis. There are very few outward signs of Fragile X syndrome. Mental retardation is the hallmark of this condition and, in females, about the only finding.

Treatment: There is no specific treatment of Fragile X syndrome. Instead, effort is directed toward training and education of the child with this condition.

Prognosis: The outcome depends on the extent of retardation.

Complications: Complications vary depending on the type and severity of symptoms.

Call for an appointment with your health care provider if you suspect the possibility of fragile X syndrome in a child with mental retardation.